8 June 1966: During a publicity photo formation flight, a Lockheed F-104N Starfighter, N813NA, flown by NASA Chief Research Test Pilot Joseph A. Walker, was caught in the wingtip vortices of the North American Aviation XB-70A-2 Valkyrie, 62-0207, the second prototype Mach 3+ strategic bomber. The Starfighter rolled up and across the Valkyrie. The two airplanes collided, with the F-104 taking off the Valkyrie’s vertical fins, then exploding.
The Valkyrie continued to fly straight and level for 16 seconds before it began to roll inverted. The B-70’s pilot, Alvin S. White, was able to eject, though he was severely injured. Joe Walker and B-70 co-pilot Major Carl S. Cross, United States Air Force, were killed.
Still photographs and motion picture film of the formation were being taken from Clay Lacy’s Gates Lear Jet. The photos were for a General Electric publicity campaign showing U.S. military aircraft that were powered by GE engines. Air Force procedures for requesting and approval of publicity flights were not properly followed and it is likely this flight would not have been approved had they been.
Reportedly, just prior to the collision, Walker radioed, “I’m opposing this mission. It is too turbulent and it has no scientific value.”
11 May 1964: At Air Force Plant 42 near Palmdale, a small city in the high desert of southern California, the first prototype North American Aviation XB-70A-1-NA Valkyrie, 62-0001, was rolled out. More than 5,000 people were there to watch.
In August 1960, the U.S. Air Force had contracted for one XB-70 prototype and 11 pre-production YB-70 development aircraft. By 1964, however, the program had been scaled back to two XB-70As and one XB-70B. Only two were actually completed.
The B-70 was designed as a Mach 3+ strategic bomber capable of flying higher than 70,000 feet (21,336 meters). Like its contemporaries, the Lockheed Blackbirds, the Valkerie was so advanced that it was beyond the state of the art. New materials and processes had to be developed, and new industrial machinery designed and built.
The XB-70A is a very large aircraft with a canard-delta configuration, built primarily of stainless steel and titanium. It has twin vertical fins combining the functions of stabilizers and rudders. The XB-70A Valkyrie prototype is 193 feet, 5 inches (58.953 meters) long, including the pitot boom, with a wingspan of 105 feet, 0 inches (32.004 meters) and overall height of 30 feet, 9 inches (9.373 meters). The canard span is 28 feet, 10 inches (8.788 meters). The canard has flaps, while the delta wing used multiple separate elevons for pitch and roll control.
The delta wing has an angle of incidence of 0° and its leading edges are swept to 65.57°, with 0° sweep at the trailing edge. The wings have a maximum of -2.60° of twist. The wings of 62-001 have no dihedral, but the second B-70, 62-0207, had 5° dihedral. The total wing area is 6,297.8 square feet (585.1 square meters).
The canard also has 0° of incidence and dihedral. Its leading edge is swept aft 31.70°, while the trailing edge sweeps forward 14.91°. The canard has a total area of 415.59 square feet (38.61 square meters). The canard flaps can be lowered to 20°.
The vertical fins have a height of 15 feet (4.572 meters). The leading edges are swept 51.77° and the trailing edges, 10.89°.
The B-70 was designed to “surf” on its own supersonic shock wave (this was called “compression lift”). The outer 20 feet (6.096 meters) of each wing could be lowered to a 25° or 65° angle for high speed flight. Although this did provide additional directional stability, it actually helped increase the compression lift, which supported up to 35% of the airplane’s weight in flight.
The first prototype, 62-001, had an empty weight of 231,215 pounds (104,877 kilograms), an its maximum takeoff weight was 521,056 pounds (236,347 kilograms).
The XB-70A is powered by six General Electric YJ93-GE-3 engines, grouped together in the tail. These are single-spool, axial-flow, afterburning turbojet engines, which have an 11-stage compressor section and 2-stage turbine. The YJ93-GE-3 has a normal power rating of 17,700 pounds of thrust (78.734 kilonewtons); military power, 19,900 pounds (88.520 kilonewtons); and maximum power, 28,000 pounds (124.550 kilonewtons). All ratings are at 6,825 r.p.m. and are continuous. A special high-temperature fuel, JP-6, is required. The engine is 19 feet, 8.3 inches (6.002 meters) long, 4 feet, 6.15 inches (1.375 meters) in diameter, and weighs 5,220 pounds (2,368 kilograms).
62-0001 had a cruise speed of 1,089 knots (1,253 miles per hour/2,016 kilometers per hour) at 35,000 feet (10,688 meters), and maximum speed of 1,721 knots (1,980 miles per hour/3,187 kilometers per hour) at 79,050 feet (24,094 meters)—Mach 2.97. During flight testing, the XB-70A reached a maximum of Mach 3.08 (1,777 knots) with a sustained altitude of 74,000 feet (22,555 meters).
Fuel was carried in 11 internal tanks in the wings and fuselage and the maximum capacity was 43,646 gallons (165,218 liters), giving the bomber a combat range of 3,786 nautical miles (4,357 statute miles/7,012 kilometers).
The B-70 was designed to carry two B-53 two-stage radiation-implosion thermonuclear bombs in its internal bomb bay. A maximum of fourteen smaller weapons could be carried.
XB-70A-1 62-0001 first flew 21 September 1964, and exceeded Mach 3 for the first time on its 17th flight, 14 October 1965. Its final flight was 4 February 1969.
The second prototype, XB-70A-2-NA 62-0207, was destroyed in a midair collision. The third Valkyrie, XB-70B-NA 62-0208, was cancelled before completion.
62-0001 is in the collection of the National Museum of the United States Air Force. It has made 83 flights with just 160 hours, 16 minutes, total flight time.
4 February 1969: The North American Aviation XB-70A-1-NA Valkyrie, 62-0001, made its very last flight from Edwards Air Force Base, California, to Wright-Patterson Air Force Base, Ohio. NASA Research Test Pilot Fitzhugh L. Fulton, Jr., Lieutenant Colonel, U.S. Air Force (Retired), and Lieutenant Colonel Emil Sturmthal, U.S. Air Force, were the flight crew for this final flight.
On arrival at Wright-Patterson, Fulton closed out the log book and handed it over to the curator of the National Museum of the United States Air Force.
The Mach 3+ prototype strategic bomber and high-speed, high-altitude research airplane had completed 83 flights for a total of 160 hours, 16 minutes of flight time.
62-0001 was the first of three prototype Mach 3+ strategic bombers. (The third prototype, XB-70B 62-0208, was not completed.) The Valkyrie utilized the most advanced technology available. Materials and manufacturing techniques had to be developed specifically to build this airplane. It is a large delta wing airplane with a forward canard and two vertical fins. The outer 20 feet (6.096 meters) of each wing could be lowered to a 25° or 65° angle for high speed flight. Although this did provide additional directional stability, it actually helped increase the compression lift, which supported up to 35% of the airplane’s weight in flight.
The XB-70A is 185 feet, 10 inches (56.642 meters) long with a wingspan of 105 feet (32.004 meters) and overall height of 30 feet, 9 inches (9.373 meters). Fully loaded, the Valkyrie weighs 534,700 pounds (242,535 kilograms).
It is powered by six General Electric YJ93-GE-3 turbojet engines which were rated at 22,000 pounds of thrust (97.86 kilonewtons) at Sea Level, and 31,000 pounds (137.89 kilonewtons) with afterburner. The J93 was a single-shaft axial-flow turbojet with an 11-stage compressor section and two-stage turbine. It was 235.0 inches (5.969 meters) long, 55.0 inches (1.397 meters) in diameter, and weighed 4,770 pounds (2,164 kilograms).
The maximum speed achieved was Mach 3.1 (2,056 miles per hour, or 3,308.8 kilometers per hour) at 73,000 feet (22,250 meters). The service ceiling is 73,350 feet (23,357 meters).
The second Valkyrie, XB-70A-2-NA 62-0207, was destroyed when it crashed after a mid-air collision with a Lockheed F-104N Starfighter flown by NASA Chief Research Test Pilot Joseph A. Walker, 8 June 1966. Both Walker and the B-70’s co-pilot, Major Carl S. Cross, U.S. Air Force, were killed.
XB-70A Valkyrie 62-0001 is in the collection of the National Museum of the United States Air Force.
21 September 1964: The first prototype North American Aviation XB-70A-1-NA Valkyrie, serial number 62-0001, flown by Chief Test Pilot Alvin S. White and Colonel Joseph F. Cotton, U.S. Air Force, made its first flight from Air Force Plant 42, Palmdale, California, to Edwards Air Force Base.
Originally a prototype Mach 3 strategic bomber, 62-0001 (also known as AV-1) and it’s sister ship, XB-70A-2-NA, 62-0207, (AV-2), were built and used by the Air Force and NASA as high-speed research aircraft. The third Valkyrie, XB-70B-NA 62-0208 (AV-3), was never completed.
The B-70 was designed as a high-altitude Mach 3 strategic bomber armed with thermonuclear bombs. The XB-70A is 196 feet, 6 inches (59.893 meters) long with a wingspan of 105 feet (32.004 meters) and an overall height of 30 feet, 8 inches (9.347 meters). It weighs 231,215 pounds (104,877 kilograms) empty and has a maximum takeoff weight of 534,792 pounds (242,578 kilograms).
The XB-70’s delta wing had a total area of 6,297 square feet (585.01 square meters). it had a sweep of 58.0° at 25% chord. The angle of incidence was 0° and the wing incorporated 3.0° negative twist. There was no dihedral. (The second XB-70 had 5° dihedral.) The outer wing panels could be lowered as much as 60° to increase longitudinal stability in high speed flight.
The XB-70A was powered by six General Electric YJ93-GE-3 single-spool, axial-flow turbojet engines, which used an 11-stage compressor and two-stage turbine. The engine required a special heat-resistant JP-6 fuel. It had a maximum continuous power rating of 28,000 pounds of thrust (124.55 kilonewtons) at 6,825 r.p.m. The YJ93-GE-3 was 19 feet, 8.3 inches (6.002 meters) long, 4 feet, 6.15 inches (1.375 meters) in diameter, and weighed 5,220 pounds (2,368 kilograms).
The XB-70A had a maximum speed of Mach 3.1 (2,056 miles per hour, or 3,309 kilometers per hour). At 35,000 feet (10,668 meters), it could reach Mach 1.90 (1,254 miles per hour, or 2,018 kilometers per hour), and at its service ceiling of 75,550 feet (23,012 meters), it had a maximum speed of Mach 3.00 (1,982 miles per hour, or 3,190 kilometers per hour). The planned combat range for the production bomber was 3,419 miles (5,502 kilometers) with a maximum range of 4,290 miles (6,904 kilometers).
North American Aviation XB-70A Valkyrie 62-0001 made 83 flights with a total of 160 hours, 16 minutes flight time. 62-0001 is on display at the National Museum of the United States Air Force, Wright-Patterson Air Force Base, Ohio.